Wednesday, August 17, 2016

Auditory cues for directions and distance

Smart phones provide facilities that can be used in new ways to help the visually challenged. They can also be used to help vehicle operators like pilots and car drivers. They could be important in special environments like space and underwater. 

Imagine a visually challenged student on the school playgrounds. A beep-beep sound at a set frequency can give him information about the direction and distance of the entrance of the main building from his current position. Assuming that he listens to this information through stereo earphones, the directional cue could be given by a suitable, short delay between the signals sent to the two ears. Further, the signal sent to the ear facing the school main gate could be louder by a computed amount. Important locations like the main building entrance could be marked by a cell phone acting as a GPS beacons for this purpose, broadcasting an ID number and a code indicating the nature of auditory cue that the listener should receive. The student’s smartphone would have a good compass that gives the software a reading of the direction the student is facing at a given instance. In future there could be a gyroscopic sensor to provide short term accuracy in direction sensing. 
It is possible to represent a direction, say north, by a steady whistle at a low volume. This could be in the form of a common complex waveform sent to the two ears, but one of them being delayed in a suitable manner, enabling the user to sense where north is in relation to the direction he is facing.
Multiple locations can be represented simultaneously by different types of beeps. Two dimensions are available to uniquely identify a signal – one being the number of beeps/second, and the other, the frequency of the underlying sub-carrier that carries the beep. Either one of these cues could give distance information. 
Some interesting research questions are:
1.   How many different locations can be signaled effectively?
2.   Can we offer training to increase the number of locations that a user can be aware of at a given time?
3.   What are the best ways of presenting distance/direction information to a user?
4.   Do we always need earphones? Or, can we use stereo-speakers in a car to give the driver some information about cars near him that he cannot see?
5.   Can the car speakers also give the driver information about other vehicles approaching or receding from his own? Can this, for instance, be done by change of the sub-carrier frequency carrying the beeps representing one of the nearby cars?
6.   What is a good auditory code to represent a section of a street? For instance, could a street be represented by a few virtual objects moving up and down the street, sending appropriate beeps?

No comments: